Astronomer

Potential Student Projects

A number of potential graduate student projects are listed below. Nothing is set in stone, so please just get in touch if some aspect of these interests you, or you would like to be involved in a project described elsewhere on the site. It is usual to have multiple supervisors, so some potential options are also listed here, although these can of course also be adapted to bring in relevant expertise at UWA, elsewhere in Australia, or internationally.

Our understanding of the Universe is dominated by studies at optical wavelengths, and the emission from stars. While such studies have led to huge advances in our understanding of galaxy evolution, they can only reveal part of the picture. A crucial extra ingredient to study is the material that stars are made of - gas. The Square Kilometre Array and its pathfinders will lead to huge advances in this field, enabling studies of the emission from neutral atomic hydrogen at much larger distances than ever before. This project will aim to make use of data from two of the leading deep astronomical surveys currently underway (the CHILES survey being carried out on the Very Large Array in New Mexico, USA, and early science data from the DINGO survey on the Australian Square Kilometre Array Pathfinder) to create some of the most distant images of the atomic hydrogen content of galaxies ever made. These surveys are highly data intensive, with the data products for DINGO ultimately expected to exceed 1PB in size. This project will explore new methods to deliver the best possible survey images and refine the pipelines required to analyse data on such a massive scale. Research work will be carried out on the Galaxy and Magnus supercomputers at Pawsey, along with cutting edge resources available through the Amazon Web Services. Collaboration with colleagues in the United Kingdom is also expected, with this work directly relevant to the successful delivery of science with the Square Kilometre Array.

The era of the Square Kilometre Array presents many exciting challenges. For large surveys of the sky (be it wide-area studies of the nearby Universe or deep studies looking back in time) one of these challenges is locating the emission from galaxies in the huge amounts of data the next generation of telescopes will deliver. New algorithms are significantly advancing our abilities to automatically detect and parametrize the signals from astronomical sources, yet a number of important avenues remain unexplored. This project will investigate new ways in which we can deliver the most complete and accurate galaxy catalogues possible, be that through the use of optical redshift data to provide robust priors on the locations of galaxies, or the development of new methodologies, such as machine learning algorithms, to refine the reliability of automatically generated sources catalogues. This work is vital to the successful completion of spectral line surveys over the coming decades, in which billions of dollars of radio astronomy research infrastructure is now being developed and for which many millions of galaxies are going to need to be automatically identified and characterised. This project will make use of ASKAP early science data, and that from existing facilities, to make new measurements of the environmental dependence of the HI mass function, gas-fraction scaling relationships, and the cosmic density of HI.

Image: Simulated galaxy distributions from the DINGO and WALLABY surveys on ASKAP, the image cubes from which are expected to contain ~600,000 galaxies.

The material in galaxies is not at rest. In the disks of late-type ‘spiral’ galaxies it orbits galactic centres at ~100,000s of kilometres per hour, on top of local turbulent motions and the more radical processes driving material both in, and out of, galactic disks altogether. The 21cm line of neutral hydrogen is an excellent tracer of these motions, providing unique insight into the dynamical nature of galaxies, their angular momentum, the regulation of galactic structure, and the nature of their hidden dark matter haloes. This project will align neutral atomic hydrogen data from current and future HI surveys (including ASKAP early science data) with that from cutting edge multi-wavelength datasets (including 3-dimensional optical IFU datasets) to shed new light on galaxy dynamics and help understand how the rich diversity of galactic structures in the Universe came to be. How has the angular momentum distribution in galaxies changed with time? What is balance of ordered and random motion? What drives the redistribution of material within galaxies? How do the local dynamical properties of galaxies correlate with their environment?

The distribution of matter in the Universe is not homogenous, but rather forms a complex web of walls, filaments, groups and clusters. Galaxies act as trace particles for this complex structure filling the Universe, with the underlying structure being dominated by Dark Matter and highly ionised gas. While extremely important for understanding how galaxies were able to grow and continue to form stars over the history of the Universe, this highly ionised material is extremely difficult to observe. This project will explore new ways of detecting the hidden cosmic web at radio wavelengths, through continuum observations for synchrotron emission, to deep spectral line observations for the small amount of neutral hydrogen still expected to be exist between and around galaxies. With a view towards future observations with FAST, the five hundred metre aperture telescope nearing completion in China, along with deep future surveys with the MeerKAT Square Kilometre Array pathfinder in South Africa, this project aims to advance our observational limits for one of the most elusive components of the baryonic Universe.